/*
 * Copyright (c) 2013, 2019, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package com.oracle.svm.core.posix.linux;

import org.graalvm.nativeimage.StackValue;

import com.oracle.svm.core.Uninterruptible;
import com.oracle.svm.core.annotate.Substitute;
import com.oracle.svm.core.annotate.TargetClass;
import com.oracle.svm.core.posix.PosixUtils;
import com.oracle.svm.core.posix.headers.Time;
import com.oracle.svm.core.posix.headers.linux.LinuxTime;
import com.oracle.svm.core.util.TimeUtils;

import java.util.Objects;

@TargetClass(java.lang.System.class)
final class Target_java_lang_System_Linux {

    @Substitute
    @Uninterruptible(reason = "Does basic math after a simple system call")
    private static long nanoTime() {
        Time.timespec tp = StackValue.get(Time.timespec.class);
        int status = LinuxTime.NoTransitions.clock_gettime(LinuxTime.CLOCK_MONOTONIC(), tp);
        PosixUtils.checkStatusIs0(status, "System.nanoTime(): clock_gettime(CLOCK_MONOTONIC) failed.");
        return tp.tv_sec() * TimeUtils.nanosPerSecond + tp.tv_nsec();
    }

    @Substitute
    public static String mapLibraryName(String libname) {
        Objects.requireNonNull(libname);
        return "lib" + libname + ".so";
    }
}

/** Dummy class to have a class with the file's name. */
public final class LinuxSubstitutions {
}
